Surface coverings such as decorative decals, stripes, graphics, emblems, and protective moldings are used extensively in a variety of applications. These surface coverings are typically adhered with pressure-sensitive adhesives to painted and unpainted surfaces of automobiles, trucks, airplanes, and boats. The pressure sensitive adhesives typically are based on acrylic polymers or elastomers which may have been modified by the addition of tackifiers and stabilizers to enable the surface covering item to adhere to the surface by finger or roller pressure.
In the process of repairing and repainting portions of a painted surface to which the surface coverings are adhered, removal of the coverings may be necessary. Removal of relatively thin surface coverings such as decals and pinstripes is presently done by removing the covering from the painted surface with a hand- or tool-held razor blade. Typically, this cutting process leaves the adhesive and small fragments of the surface covering on the surface which must thereafter be removed by vigorously rubbing the residue with a cloth or sponge soaked with a suitable solvent. Use of a razor blade may also damage the underlying surface paint.
Another removal procedure employs a heat gun to very carefully heat the surface covering so that a thin object such as a fingernail may be inserted under a softened edge to start removal and thereafter pulling on the edge to remove the remainder of the surface covering. However, relatively thin decals and stripes often do not have high tensile strength and usually tear free from the unremoved portion, thereby requiring the removal procedure to be initiated again. This procedure has the disadvantages of potentially overheating and damaging the painted surface from which the surface covering is removed, and it is a very tedious task.
Another existing problem occurs when emblems and protective side moldings on an automobile or truck are peeled from a surface. Adhesive residue is often left on both the emblem or molding and the painted surface of the automobile. The adhesive residue then must be removed from both surfaces, such as by vigorously rubbing the residue with a cloth or sponge soaked with a suitable solvent which is selected so that it will dissolve the adhesive residue but not harm the painted surface which bears it. While more aggressive solvents may facilitate faster removal of the adhesives, such solvents can damage some painted surfaces and may raise flammability and/or toxicity concerns. The adhesive residue on the emblem or the side molding must also be removed, usually by scraping, followed by solvent cleanup.
In response to these problems, systems have been developed that utilize a rotating polymeric disc. When the rotating disc is contacted with the surface covering, the resulting friction causes an increase in temperature. This temperature increase causes the adhesive to soften, and the emblem or molding can then be removed. An example of such a system is found in Winter, U.S. Pat. No. 5,269,874. Such systems have alleviated many of the above noted problems associated with the removal of adhered surface coverings. However, other concerns arise with rotating disc systems. For example, the hardness and abrasive properties of the disc must be controlled to ensure that the surface covering is removed without damaging the substrate. If the disc is too soft, insufficient heat will be generated and/or the disc material will smear onto the surface. If the temperature at the surface is too high, the underlying paint can be cracked or damaged, or airborne residue known as "fog" can be generated.